// format parses src, prints the corresponding AST, verifies the resulting
// src is syntactically correct, and returns the resulting src or an error
// if any.
func format(src []byte, mode checkMode) ([]byte, error) {
// parse src
f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
if err != nil {
return nil, fmt.Errorf("parse: %s\n%s", err, src)
}
// filter exports if necessary
if mode&export != 0 {
ast.FileExports(f) // ignore result
f.Comments = nil // don't print comments that are not in AST
}
// determine printer configuration
cfg := Config{Tabwidth: tabwidth}
if mode&rawFormat != 0 {
cfg.Mode |= RawFormat
}
// print AST
var buf bytes.Buffer
if err := cfg.Fprint(&buf, fset, f); err != nil {
return nil, fmt.Errorf("print: %s", err)
}
// make sure formated output is syntactically correct
res := buf.Bytes()
if _, err := parser.ParseFile(fset, "", res, 0); err != nil {
return nil, fmt.Errorf("re-parse: %s\n%s", err, buf.Bytes())
}
return res, nil
}
func parse(fset *token.FileSet, src []byte) (interface{}, error) {
// Try as a complete source file.
file, err := parser.ParseFile(fset, "", src, parser.ParseComments)
if err == nil {
return file, nil
}
// If the source is missing a package clause, try as a source fragment; otherwise fail.
if !strings.Contains(err.Error(), "expected 'package'") {
return nil, err
}
// Try as a declaration list by prepending a package clause in front of src.
// Use ';' not '\n' to keep line numbers intact.
psrc := append([]byte("package p;"), src...)
file, err = parser.ParseFile(fset, "", psrc, parser.ParseComments)
if err == nil {
return file.Decls, nil
}
// If the source is missing a declaration, try as a statement list; otherwise fail.
if !strings.Contains(err.Error(), "expected declaration") {
return nil, err
}
// Try as statement list by wrapping a function around src.
fsrc := append(append([]byte("package p; func _() {"), src...), '}')
file, err = parser.ParseFile(fset, "", fsrc, parser.ParseComments)
if err == nil {
return file.Decls[0].(*ast.FuncDecl).Body.List, nil
}
// Failed, and out of options.
return nil, err
}
func TestExamples(t *testing.T) {
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "test.go", strings.NewReader(exampleTestFile), parser.ParseComments)
if err != nil {
t.Fatal(err)
}
for i, e := range doc.Examples(file) {
c := exampleTestCases[i]
if e.Name != c.Name {
t.Errorf("got Name == %q, want %q", e.Name, c.Name)
}
if w := c.Play; w != "" {
var g string // hah
if e.Play == nil {
g = "<nil>"
} else {
var buf bytes.Buffer
if err := format.Node(&buf, fset, e.Play); err != nil {
t.Fatal(err)
}
g = buf.String()
}
if g != w {
t.Errorf("%s: got Play == %q, want %q", c.Name, g, w)
}
}
if g, w := e.Output, c.Output; g != w {
t.Errorf("%s: got Output == %q, want %q", c.Name, g, w)
}
}
}
// Verify that the printer produces a correct program
// even if the position information of comments introducing newlines
// is incorrect.
func TestBadComments(t *testing.T) {
const src = `
// first comment - text and position changed by test
package p
import "fmt"
const pi = 3.14 // rough circle
var (
x, y, z int = 1, 2, 3
u, v float64
)
func fibo(n int) {
if n < 2 {
return n /* seed values */
}
return fibo(n-1) + fibo(n-2)
}
`
f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
if err != nil {
t.Error(err) // error in test
}
comment := f.Comments[0].List[0]
pos := comment.Pos()
if fset.Position(pos).Offset != 1 {
t.Error("expected offset 1") // error in test
}
testComment(t, f, len(src), &ast.Comment{Slash: pos, Text: "//-style comment"})
testComment(t, f, len(src), &ast.Comment{Slash: pos, Text: "/*-style comment */"})
testComment(t, f, len(src), &ast.Comment{Slash: pos, Text: "/*-style \n comment */"})
testComment(t, f, len(src), &ast.Comment{Slash: pos, Text: "/*-style comment \n\n\n */"})
}
func parseFile(fset *token.FileSet, filename string, mode parser.Mode) (*ast.File, error) {
src, err := ReadFile(fs, filename)
if err != nil {
return nil, err
}
return parser.ParseFile(fset, filename, src, mode)
}
// TestLineComments, using a simple test case, checks that consequtive line
// comments are properly terminated with a newline even if the AST position
// information is incorrect.
//
func TestLineComments(t *testing.T) {
const src = `// comment 1
// comment 2
// comment 3
package main
`
fset := token.NewFileSet()
f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
if err != nil {
panic(err) // error in test
}
var buf bytes.Buffer
fset = token.NewFileSet() // use the wrong file set
Fprint(&buf, fset, f)
nlines := 0
for _, ch := range buf.Bytes() {
if ch == '\n' {
nlines++
}
}
const expected = 3
if nlines < expected {
t.Errorf("got %d, expected %d\n", nlines, expected)
t.Errorf("result:\n%s", buf.Bytes())
}
}
func TestFilterDuplicates(t *testing.T) {
// parse input
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "", input, 0)
if err != nil {
t.Fatal(err)
}
// create package
files := map[string]*ast.File{"": file}
pkg, err := ast.NewPackage(fset, files, nil, nil)
if err != nil {
t.Fatal(err)
}
// filter
merged := ast.MergePackageFiles(pkg, ast.FilterFuncDuplicates)
// pretty-print
var buf bytes.Buffer
if err := format.Node(&buf, fset, merged); err != nil {
t.Fatal(err)
}
output := buf.String()
if output != golden {
t.Errorf("incorrect output:\n%s", output)
}
}
func pkgName(filename string) string {
// use a new file set each time in order to not pollute the indexer's
// file set (which must stay in sync with the concatenated source code)
file, err := parser.ParseFile(token.NewFileSet(), filename, nil, parser.PackageClauseOnly)
if err != nil || file == nil {
return ""
}
return file.Name.Name
}
// addFile adds a file to the index if possible and returns the file set file
// and the file's AST if it was successfully parsed as a Go file. If addFile
// failed (that is, if the file was not added), it returns file == nil.
func (x *Indexer) addFile(filename string, goFile bool) (file *token.File, ast *ast.File) {
// open file
f, err := fs.Open(filename)
if err != nil {
return
}
defer f.Close()
// The file set's base offset and x.sources size must be in lock-step;
// this permits the direct mapping of suffix array lookup results to
// to corresponding Pos values.
//
// When a file is added to the file set, its offset base increases by
// the size of the file + 1; and the initial base offset is 1. Add an
// extra byte to the sources here.
x.sources.WriteByte(0)
// If the sources length doesn't match the file set base at this point
// the file set implementation changed or we have another error.
base := x.fset.Base()
if x.sources.Len() != base {
panic("internal error: file base incorrect")
}
// append file contents (src) to x.sources
if _, err := x.sources.ReadFrom(f); err == nil {
src := x.sources.Bytes()[base:]
if goFile {
// parse the file and in the process add it to the file set
if ast, err = parser.ParseFile(x.fset, filename, src, parser.ParseComments); err == nil {
file = x.fset.File(ast.Pos()) // ast.Pos() is inside the file
return
}
// file has parse errors, and the AST may be incorrect -
// set lines information explicitly and index as ordinary
// text file (cannot fall through to the text case below
// because the file has already been added to the file set
// by the parser)
file = x.fset.File(token.Pos(base)) // token.Pos(base) is inside the file
file.SetLinesForContent(src)
ast = nil
return
}
if isText(src) {
// only add the file to the file set (for the full text index)
file = x.fset.AddFile(filename, x.fset.Base(), len(src))
file.SetLinesForContent(src)
return
}
}
// discard possibly added data
x.sources.Truncate(base - 1) // -1 to remove added byte 0 since no file was added
return
}
func parseFunc(filename, functionname string) (fun *ast.FuncDecl, fset *token.FileSet) {
fset = token.NewFileSet()
if file, err := parser.ParseFile(fset, filename, nil, 0); err == nil {
for _, d := range file.Decls {
if f, ok := d.(*ast.FuncDecl); ok && f.Name.Name == functionname {
fun = f
return
}
}
}
panic("function not found")
}
// Verify that the printer doesn't crash if the AST contains BadXXX nodes.
func TestBadNodes(t *testing.T) {
const src = "package p\n("
const res = "package p\nBadDecl\n"
f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
if err == nil {
t.Error("expected illegal program") // error in test
}
var buf bytes.Buffer
Fprint(&buf, fset, f)
if buf.String() != res {
t.Errorf("got %q, expected %q", buf.String(), res)
}
}
// testComment verifies that f can be parsed again after printing it
// with its first comment set to comment at any possible source offset.
func testComment(t *testing.T, f *ast.File, srclen int, comment *ast.Comment) {
f.Comments[0].List[0] = comment
var buf bytes.Buffer
for offs := 0; offs <= srclen; offs++ {
buf.Reset()
// Printing f should result in a correct program no
// matter what the (incorrect) comment position is.
if err := Fprint(&buf, fset, f); err != nil {
t.Error(err)
}
if _, err := parser.ParseFile(fset, "", buf.Bytes(), 0); err != nil {
t.Fatalf("incorrect program for pos = %d:\n%s", comment.Slash, buf.String())
}
// Position information is just an offset.
// Move comment one byte down in the source.
comment.Slash++
}
}
func TestDeclLists(t *testing.T) {
for _, src := range decls {
file, err := parser.ParseFile(fset, "", "package p;"+src, parser.ParseComments)
if err != nil {
panic(err) // error in test
}
var buf bytes.Buffer
err = Fprint(&buf, fset, file.Decls) // only print declarations
if err != nil {
panic(err) // error in test
}
out := buf.String()
if out != src {
t.Errorf("\ngot : %q\nwant: %q\n", out, src)
}
}
}
func TestStmtLists(t *testing.T) {
for _, src := range stmts {
file, err := parser.ParseFile(fset, "", "package p; func _() {"+src+"}", parser.ParseComments)
if err != nil {
panic(err) // error in test
}
var buf bytes.Buffer
err = Fprint(&buf, fset, file.Decls[0].(*ast.FuncDecl).Body.List) // only print statements
if err != nil {
panic(err) // error in test
}
out := buf.String()
if out != src {
t.Errorf("\ngot : %q\nwant: %q\n", out, src)
}
}
}
// cannot initialize in init because (printer) Fprint launches goroutines.
func initialize() {
const filename = "testdata/parser.go"
src, err := ioutil.ReadFile(filename)
if err != nil {
log.Fatalf("%s", err)
}
file, err := parser.ParseFile(fset, filename, src, parser.ParseComments)
if err != nil {
log.Fatalf("%s", err)
}
var buf bytes.Buffer
testprint(&buf, file)
if !bytes.Equal(buf.Bytes(), src) {
log.Fatalf("print error: %s not idempotent", filename)
}
testfile = file
}
// This example demonstrates how to inspect the AST of a Go program.
func ExampleInspect() {
// src is the input for which we want to inspect the AST.
src := `
package p
const c = 1.0
var X = f(3.14)*2 + c
`
// Create the AST by parsing src.
fset := token.NewFileSet() // positions are relative to fset
f, err := parser.ParseFile(fset, "src.go", src, 0)
if err != nil {
panic(err)
}
// Inspect the AST and print all identifiers and literals.
ast.Inspect(f, func(n ast.Node) bool {
var s string
switch x := n.(type) {
case *ast.BasicLit:
s = x.Value
case *ast.Ident:
s = x.Name
}
if s != "" {
fmt.Printf("%s:\t%s\n", fset.Position(n.Pos()), s)
}
return true
})
// output:
// src.go:2:9: p
// src.go:3:7: c
// src.go:3:11: 1.0
// src.go:4:5: X
// src.go:4:9: f
// src.go:4:11: 3.14
// src.go:4:17: 2
// src.go:4:21: c
}
func ExampleParseFile() {
fset := token.NewFileSet() // positions are relative to fset
// Parse the file containing this very example
// but stop after processing the imports.
f, err := parser.ParseFile(fset, "example_test.go", nil, parser.ImportsOnly)
if err != nil {
fmt.Println(err)
return
}
// Print the imports from the file's AST.
for _, s := range f.Imports {
fmt.Println(s.Path.Value)
}
// output:
//
// "fmt"
// "go/parser"
// "go/token"
}
// Node formats node in canonical gofmt style and writes the result to dst.
//
// The node type must be *ast.File, *printer.CommentedNode, []ast.Decl,
// []ast.Stmt, or assignment-compatible to ast.Expr, ast.Decl, ast.Spec,
// or ast.Stmt. Node does not modify node. Imports are not sorted for
// nodes representing partial source files (i.e., if the node is not an
// *ast.File or a *printer.CommentedNode not wrapping an *ast.File).
//
// The function may return early (before the entire result is written)
// and return a formatting error, for instance due to an incorrect AST.
//
func Node(dst io.Writer, fset *token.FileSet, node interface{}) error {
// Determine if we have a complete source file (file != nil).
var file *ast.File
var cnode *printer.CommentedNode
switch n := node.(type) {
case *ast.File:
file = n
case *printer.CommentedNode:
if f, ok := n.Node.(*ast.File); ok {
file = f
cnode = n
}
}
// Sort imports if necessary.
if file != nil && hasUnsortedImports(file) {
// Make a copy of the AST because ast.SortImports is destructive.
// TODO(gri) Do this more efficiently.
var buf bytes.Buffer
err := config.Fprint(&buf, fset, file)
if err != nil {
return err
}
file, err = parser.ParseFile(fset, "", buf.Bytes(), parser.ParseComments)
if err != nil {
// We should never get here. If we do, provide good diagnostic.
return fmt.Errorf("format.Node internal error (%s)", err)
}
ast.SortImports(fset, file)
// Use new file with sorted imports.
node = file
if cnode != nil {
node = &printer.CommentedNode{Node: file, Comments: cnode.Comments}
}
}
return config.Fprint(dst, fset, node)
}
func TestBaseIndent(t *testing.T) {
// The testfile must not contain multi-line raw strings since those
// are not indented (because their values must not change) and make
// this test fail.
const filename = "printer.go"
src, err := ioutil.ReadFile(filename)
if err != nil {
panic(err) // error in test
}
file, err := parser.ParseFile(fset, filename, src, 0)
if err != nil {
panic(err) // error in test
}
var buf bytes.Buffer
for indent := 0; indent < 4; indent++ {
buf.Reset()
(&Config{Tabwidth: tabwidth, Indent: indent}).Fprint(&buf, fset, file)
// all code must be indented by at least 'indent' tabs
lines := bytes.Split(buf.Bytes(), []byte{'\n'})
for i, line := range lines {
if len(line) == 0 {
continue // empty lines don't have indentation
}
n := 0
for j, b := range line {
if b != '\t' {
// end of indentation
n = j
break
}
}
if n < indent {
t.Errorf("line %d: got only %d tabs; want at least %d: %q", i, n, indent, line)
}
}
}
}
func TestCommentMap(t *testing.T) {
fset := token.NewFileSet()
f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
if err != nil {
t.Fatal(err)
}
cmap := NewCommentMap(fset, f, f.Comments)
// very correct association of comments
for n, list := range cmap {
key := fmt.Sprintf("%2d: %T", fset.Position(n.Pos()).Line, n)
got := ctext(list)
want := res[key]
if got != want {
t.Errorf("%s: got %q; want %q", key, got, want)
}
}
// verify that no comments got lost
if n := len(cmap.Comments()); n != len(f.Comments) {
t.Errorf("got %d comment groups in map; want %d", n, len(f.Comments))
}
// support code to update test:
// set genMap to true to generate res map
const genMap = false
if genMap {
out := make([]string, 0, len(cmap))
for n, list := range cmap {
out = append(out, fmt.Sprintf("\t\"%2d: %T\":\t%q,", fset.Position(n.Pos()).Line, n, ctext(list)))
}
sort.Strings(out)
for _, s := range out {
fmt.Println(s)
}
}
}
// Import returns details about the Go package named by the import path,
// interpreting local import paths relative to the srcDir directory.
// If the path is a local import path naming a package that can be imported
// using a standard import path, the returned package will set p.ImportPath
// to that path.
//
// In the directory containing the package, .go, .c, .h, and .s files are
// considered part of the package except for:
//
// - .go files in package documentation
// - files starting with _ or . (likely editor temporary files)
// - files with build constraints not satisfied by the context
//
// If an error occurs, Import returns a non-nil error and a non-nil
// *Package containing partial information.
//
func (ctxt *Context) Import(path string, srcDir string, mode ImportMode) (*Package, error) {
p := &Package{
ImportPath: path,
}
if path == "" {
return p, fmt.Errorf("import %q: invalid import path", path)
}
var pkga string
var pkgerr error
switch ctxt.Compiler {
case "gccgo":
dir, elem := pathpkg.Split(p.ImportPath)
pkga = "pkg/gccgo_" + ctxt.GOOS + "_" + ctxt.GOARCH + "/" + dir + "lib" + elem + ".a"
case "gc":
suffix := ""
if ctxt.InstallSuffix != "" {
suffix = "_" + ctxt.InstallSuffix
}
pkga = "pkg/" + ctxt.GOOS + "_" + ctxt.GOARCH + suffix + "/" + p.ImportPath + ".a"
default:
// Save error for end of function.
pkgerr = fmt.Errorf("import %q: unknown compiler %q", path, ctxt.Compiler)
}
binaryOnly := false
if IsLocalImport(path) {
pkga = "" // local imports have no installed path
if srcDir == "" {
return p, fmt.Errorf("import %q: import relative to unknown directory", path)
}
if !ctxt.isAbsPath(path) {
p.Dir = ctxt.joinPath(srcDir, path)
}
// Determine canonical import path, if any.
if ctxt.GOROOT != "" {
root := ctxt.joinPath(ctxt.GOROOT, "src", "pkg")
if sub, ok := ctxt.hasSubdir(root, p.Dir); ok {
p.Goroot = true
p.ImportPath = sub
p.Root = ctxt.GOROOT
goto Found
}
}
all := ctxt.gopath()
for i, root := range all {
rootsrc := ctxt.joinPath(root, "src")
if sub, ok := ctxt.hasSubdir(rootsrc, p.Dir); ok {
// We found a potential import path for dir,
// but check that using it wouldn't find something
// else first.
if ctxt.GOROOT != "" {
if dir := ctxt.joinPath(ctxt.GOROOT, "src", "pkg", sub); ctxt.isDir(dir) {
p.ConflictDir = dir
goto Found
}
}
for _, earlyRoot := range all[:i] {
if dir := ctxt.joinPath(earlyRoot, "src", sub); ctxt.isDir(dir) {
p.ConflictDir = dir
goto Found
}
}
// sub would not name some other directory instead of this one.
// Record it.
p.ImportPath = sub
p.Root = root
goto Found
}
}
// It's okay that we didn't find a root containing dir.
// Keep going with the information we have.
} else {
if strings.HasPrefix(path, "/") {
return p, fmt.Errorf("import %q: cannot import absolute path", path)
}
// tried records the location of unsuccessful package lookups
var tried struct {
goroot string
gopath []string
}
// Determine directory from import path.
if ctxt.GOROOT != "" {
dir := ctxt.joinPath(ctxt.GOROOT, "src", "pkg", path)
isDir := ctxt.isDir(dir)
binaryOnly = !isDir && mode&AllowBinary != 0 && pkga != "" && ctxt.isFile(ctxt.joinPath(ctxt.GOROOT, pkga))
if isDir || binaryOnly {
p.Dir = dir
p.Goroot = true
p.Root = ctxt.GOROOT
goto Found
}
tried.goroot = dir
}
for _, root := range ctxt.gopath() {
dir := ctxt.joinPath(root, "src", path)
isDir := ctxt.isDir(dir)
binaryOnly = !isDir && mode&AllowBinary != 0 && pkga != "" && ctxt.isFile(ctxt.joinPath(root, pkga))
if isDir || binaryOnly {
p.Dir = dir
p.Root = root
goto Found
}
tried.gopath = append(tried.gopath, dir)
}
// package was not found
var paths []string
if tried.goroot != "" {
paths = append(paths, fmt.Sprintf("\t%s (from $GOROOT)", tried.goroot))
} else {
paths = append(paths, "\t($GOROOT not set)")
}
var i int
var format = "\t%s (from $GOPATH)"
for ; i < len(tried.gopath); i++ {
if i > 0 {
format = "\t%s"
}
paths = append(paths, fmt.Sprintf(format, tried.gopath[i]))
}
if i == 0 {
paths = append(paths, "\t($GOPATH not set)")
}
return p, fmt.Errorf("cannot find package %q in any of:\n%s", path, strings.Join(paths, "\n"))
}
Found:
if p.Root != "" {
if p.Goroot {
p.SrcRoot = ctxt.joinPath(p.Root, "src", "pkg")
} else {
p.SrcRoot = ctxt.joinPath(p.Root, "src")
}
p.PkgRoot = ctxt.joinPath(p.Root, "pkg")
p.BinDir = ctxt.joinPath(p.Root, "bin")
if pkga != "" {
p.PkgObj = ctxt.joinPath(p.Root, pkga)
}
}
if mode&FindOnly != 0 {
return p, pkgerr
}
if binaryOnly && (mode&AllowBinary) != 0 {
return p, pkgerr
}
dirs, err := ctxt.readDir(p.Dir)
if err != nil {
return p, err
}
var Sfiles []string // files with ".S" (capital S)
var firstFile string
imported := make(map[string][]token.Position)
testImported := make(map[string][]token.Position)
xTestImported := make(map[string][]token.Position)
allTags := make(map[string]bool)
fset := token.NewFileSet()
for _, d := range dirs {
if d.IsDir() {
continue
}
name := d.Name()
ext := nameExt(name)
match, data, filename, err := ctxt.matchFile(p.Dir, name, true, allTags)
if err != nil {
return p, err
}
if !match {
if ext == ".go" {
p.IgnoredGoFiles = append(p.IgnoredGoFiles, name)
}
continue
}
// Going to save the file. For non-Go files, can stop here.
switch ext {
case ".c":
p.CFiles = append(p.CFiles, name)
continue
case ".cc", ".cpp", ".cxx":
p.CXXFiles = append(p.CXXFiles, name)
continue
case ".h", ".hh", ".hpp", ".hxx":
p.HFiles = append(p.HFiles, name)
continue
case ".s":
p.SFiles = append(p.SFiles, name)
continue
case ".S":
Sfiles = append(Sfiles, name)
continue
case ".swig":
p.SwigFiles = append(p.SwigFiles, name)
continue
case ".swigcxx":
p.SwigCXXFiles = append(p.SwigCXXFiles, name)
continue
case ".syso":
// binary objects to add to package archive
// Likely of the form foo_windows.syso, but
// the name was vetted above with goodOSArchFile.
p.SysoFiles = append(p.SysoFiles, name)
continue
}
pf, err := parser.ParseFile(fset, filename, data, parser.ImportsOnly|parser.ParseComments)
if err != nil {
return p, err
}
pkg := pf.Name.Name
if pkg == "documentation" {
p.IgnoredGoFiles = append(p.IgnoredGoFiles, name)
continue
}
isTest := strings.HasSuffix(name, "_test.go")
isXTest := false
if isTest && strings.HasSuffix(pkg, "_test") {
isXTest = true
pkg = pkg[:len(pkg)-len("_test")]
}
if p.Name == "" {
p.Name = pkg
firstFile = name
} else if pkg != p.Name {
return p, fmt.Errorf("found packages %s (%s) and %s (%s) in %s", p.Name, firstFile, pkg, name, p.Dir)
}
if pf.Doc != nil && p.Doc == "" {
p.Doc = doc.Synopsis(pf.Doc.Text())
}
// Record imports and information about cgo.
isCgo := false
for _, decl := range pf.Decls {
d, ok := decl.(*ast.GenDecl)
if !ok {
continue
}
for _, dspec := range d.Specs {
spec, ok := dspec.(*ast.ImportSpec)
if !ok {
continue
}
quoted := spec.Path.Value
path, err := strconv.Unquote(quoted)
if err != nil {
log.Panicf("%s: parser returned invalid quoted string: <%s>", filename, quoted)
}
if isXTest {
xTestImported[path] = append(xTestImported[path], fset.Position(spec.Pos()))
} else if isTest {
testImported[path] = append(testImported[path], fset.Position(spec.Pos()))
} else {
imported[path] = append(imported[path], fset.Position(spec.Pos()))
}
if path == "C" {
if isTest {
return p, fmt.Errorf("use of cgo in test %s not supported", filename)
}
cg := spec.Doc
if cg == nil && len(d.Specs) == 1 {
cg = d.Doc
}
if cg != nil {
if err := ctxt.saveCgo(filename, p, cg); err != nil {
return p, err
}
}
isCgo = true
}
}
}
if isCgo {
allTags["cgo"] = true
if ctxt.CgoEnabled {
p.CgoFiles = append(p.CgoFiles, name)
} else {
p.IgnoredGoFiles = append(p.IgnoredGoFiles, name)
}
} else if isXTest {
p.XTestGoFiles = append(p.XTestGoFiles, name)
} else if isTest {
p.TestGoFiles = append(p.TestGoFiles, name)
} else {
p.GoFiles = append(p.GoFiles, name)
}
}
if len(p.GoFiles)+len(p.CgoFiles)+len(p.TestGoFiles)+len(p.XTestGoFiles) == 0 {
return p, &NoGoError{p.Dir}
}
for tag := range allTags {
p.AllTags = append(p.AllTags, tag)
}
sort.Strings(p.AllTags)
p.Imports, p.ImportPos = cleanImports(imported)
p.TestImports, p.TestImportPos = cleanImports(testImported)
p.XTestImports, p.XTestImportPos = cleanImports(xTestImported)
// add the .S files only if we are using cgo
// (which means gcc will compile them).
// The standard assemblers expect .s files.
if len(p.CgoFiles) > 0 {
p.SFiles = append(p.SFiles, Sfiles...)
sort.Strings(p.SFiles)
}
return p, pkgerr
}
// This example shows what an AST looks like when printed for debugging.
func ExamplePrint() {
// src is the input for which we want to print the AST.
src := `
package main
func main() {
println("Hello, World!")
}
`
// Create the AST by parsing src.
fset := token.NewFileSet() // positions are relative to fset
f, err := parser.ParseFile(fset, "", src, 0)
if err != nil {
panic(err)
}
// Print the AST.
ast.Print(fset, f)
// output:
// 0 *ast.File {
// 1 . Package: 2:1
// 2 . Name: *ast.Ident {
// 3 . . NamePos: 2:9
// 4 . . Name: "main"
// 5 . }
// 6 . Decls: []ast.Decl (len = 1) {
// 7 . . 0: *ast.FuncDecl {
// 8 . . . Name: *ast.Ident {
// 9 . . . . NamePos: 3:6
// 10 . . . . Name: "main"
// 11 . . . . Obj: *ast.Object {
// 12 . . . . . Kind: func
// 13 . . . . . Name: "main"
// 14 . . . . . Decl: *(obj @ 7)
// 15 . . . . }
// 16 . . . }
// 17 . . . Type: *ast.FuncType {
// 18 . . . . Func: 3:1
// 19 . . . . Params: *ast.FieldList {
// 20 . . . . . Opening: 3:10
// 21 . . . . . Closing: 3:11
// 22 . . . . }
// 23 . . . }
// 24 . . . Body: *ast.BlockStmt {
// 25 . . . . Lbrace: 3:13
// 26 . . . . List: []ast.Stmt (len = 1) {
// 27 . . . . . 0: *ast.ExprStmt {
// 28 . . . . . . X: *ast.CallExpr {
// 29 . . . . . . . Fun: *ast.Ident {
// 30 . . . . . . . . NamePos: 4:2
// 31 . . . . . . . . Name: "println"
// 32 . . . . . . . }
// 33 . . . . . . . Lparen: 4:9
// 34 . . . . . . . Args: []ast.Expr (len = 1) {
// 35 . . . . . . . . 0: *ast.BasicLit {
// 36 . . . . . . . . . ValuePos: 4:10
// 37 . . . . . . . . . Kind: STRING
// 38 . . . . . . . . . Value: "\"Hello, World!\""
// 39 . . . . . . . . }
// 40 . . . . . . . }
// 41 . . . . . . . Ellipsis: -
// 42 . . . . . . . Rparen: 4:25
// 43 . . . . . . }
// 44 . . . . . }
// 45 . . . . }
// 46 . . . . Rbrace: 5:1
// 47 . . . }
// 48 . . }
// 49 . }
// 50 . Scope: *ast.Scope {
// 51 . . Objects: map[string]*ast.Object (len = 1) {
// 52 . . . "main": *(obj @ 11)
// 53 . . }
// 54 . }
// 55 . Unresolved: []*ast.Ident (len = 1) {
// 56 . . 0: *(obj @ 29)
// 57 . }
// 58 }
}
// Verify that the SourcePos mode emits correct //line comments
// by testing that position information for matching identifiers
// is maintained.
func TestSourcePos(t *testing.T) {
const src = `
package p
import ( "go/printer"; "math" )
const pi = 3.14; var x = 0
type t struct{ x, y, z int; u, v, w float32 }
func (t *t) foo(a, b, c int) int {
return a*t.x + b*t.y +
// two extra lines here
// ...
c*t.z
}
`
// parse original
f1, err := parser.ParseFile(fset, "src", src, parser.ParseComments)
if err != nil {
t.Fatal(err)
}
// pretty-print original
var buf bytes.Buffer
err = (&Config{Mode: UseSpaces | SourcePos, Tabwidth: 8}).Fprint(&buf, fset, f1)
if err != nil {
t.Fatal(err)
}
// parse pretty printed original
// (//line comments must be interpreted even w/o parser.ParseComments set)
f2, err := parser.ParseFile(fset, "", buf.Bytes(), 0)
if err != nil {
t.Fatalf("%s\n%s", err, buf.Bytes())
}
// At this point the position information of identifiers in f2 should
// match the position information of corresponding identifiers in f1.
// number of identifiers must be > 0 (test should run) and must match
n1 := identCount(f1)
n2 := identCount(f2)
if n1 == 0 {
t.Fatal("got no idents")
}
if n2 != n1 {
t.Errorf("got %d idents; want %d", n2, n1)
}
// verify that all identifiers have correct line information
i2range := idents(f2)
for i1 := range idents(f1) {
i2 := <-i2range
if i2.Name != i1.Name {
t.Errorf("got ident %s; want %s", i2.Name, i1.Name)
}
l1 := fset.Position(i1.Pos()).Line
l2 := fset.Position(i2.Pos()).Line
if l2 != l1 {
t.Errorf("got line %d; want %d for %s", l2, l1, i1.Name)
}
}
if t.Failed() {
t.Logf("\n%s", buf.Bytes())
}
}